#include<stdio.h>
#include<stdlib.h>

char * my_strcpy(char * strDest,const char * strSrc)
{
    if ((strDest==NULL)||(strSrc==NULL)) //[1]
    {
        printf("!!!!");
        return NULL;
    }
    char * strDestCopy=strDest;  //[3]
    while ((*strDest++=*strSrc++)!='\0'); //[4]
    return strDestCopy;
}

main()
{
    char* a;
    char* b;

    printf("%d  %d\n",a==0,b==0);

    //my_strcpy(b,a);
}
